You have quite a few options available to you to pay for a swimming pool purchase.

In today’s world, credit cards give you an option if you use the cards that offer the lowest interest rate and offer you a reward for using their card. If you do use a credit card, call the bank that issued you the card first and let them know the purchase you will be making and the amount that you will be putting on the card.
For your protection, most credit card companies will not let you make a major purchase without letting them know first. They may think someone stole your card and is using it. Some credit card companies only let you put a certain amount per day on your card. So check with the bank that issued you the card.
Home equity lines are another way to finance that swimming pool. With rates very low today, now is an excellent time to apply for these types of loans. The interest may also be tax deductable since it is considered mortgage interest (speak to your tax preparer for more information). Check with your local bank for these types of loans.
If you have a lot of monthly payments on various accounts, the consolidation loan may be something you want to look into. Combine all these payments into one payment and lower your monthly payment. Depending on the current interest rate you have for your home loan, you may be able to refinance at a lower rate and add a swimming pool payment and still have a lower payment then before.
There are also several online companies that will finance swimming pool purchases without collateral. The interest rates will vary depending on your credit rating.
For more information on pool pricing and financing see your local Medallion swimming pool dealer.